A trauma patient receives 14 units of whole blood over two hours during damage control surgery. He develops perioral tingling, carpopedal spasm, a prolonged QT interval, and worsening coagulopathy despite adequate replacement of plasma and platelets. The most likely electrolyte abnormality is:

• A Hyperkalaemia
• B Ionised hypocalcaemia from citrate chelation ✓
• C Hypermagnesaemia
• D Metabolic alkalosis with hypophosphataemia

Explanation

Citrate anticoagulant in each unit chelates ionised calcium; rapid large-volume transfusion outstrips hepatic citrate metabolism and produces symptomatic ionised hypocalcaemia, tetany, QT prolongation, and impaired clotting since calcium is factor IV. The standard practice is empirical calcium replacement during massive transfusion. Stored blood actually releases potassium, so hyperkalaemia is a competing risk, but it does not cause carpopedal spasm or QT prolongation.

Reference: Schwartz's Principles of Surgery, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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